Integrated circuit dies are used in electronic products, such as cell phones, disc players, and computers, are encapsulated in a mold material to provide protection from hostile environments and enable electrical interconnection between the integrated circuit die and an underlying substrate such as a printed circuit board (PCB). The leadframe is the central supporting structure of such a package being completely contained within the encapsulant except for the leads.
For purposes of high-volume, low-cost production of chip packages, a current industry practice is to etch or stamp a thin sheet of metal material to form a panel or strip that defines multiple leadframes. A single strip may be formed to include multiple arrays, with each such array including a multiplicity of leadframes in a particular pattern. In an integrated circuit package manufacturing process, the integrated circuit dies are mounted and wire and/or ball bonded to respective leadframes, with the encapsulant material then being applied to the strips to encapsulate the integrated circuit dies, bond connections, and portions of each of the leadframes.
After hardening of the encapsulant material, the leadframes within the strip are cut apart or singulated for purposes of producing the individual integrated circuit packages. Such singulation is typically accomplished via a saw singulation process. In this process, a saw blade is advanced along “saw streets” which extend in prescribed patterns between the leadframes as required to facilitate the separation of the leadframes from each other in the required manner.
In leadframe design, the leadframe does not define a continuous, uninterrupted surface. Rather, individual leads of the leadframe are separated from each other and from the peripheral edge of a die pad (if included in the leadframe) by narrow gaps. The die pad of the leadframe, if included therein, is the supporting structure to which the die is typically attached.
Currently, leadframe packages are limited with regard to input/output (I/O) count by the difficulties of leadframe manufacturing. At this point, fine-pitch leadframes are limited to 100 μm spacing when manufactured using current etching techniques.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.